US troops fired on thousands of Afghan civilians as they protested outside the massive US military base at Bagram on Monday.

A provincial police official said that at least one civilian was killed in the incident, but Nato asserted that no civilians had been killed or injured.

The Western military alliance claimed that soldiers had only fired "warning shots" to disperse residents after they surrounded a military patrol and attacked vehicles outside the sprawling facility with rocks and iron bars.

But Parwan province deputy police chief General Faqir Ahmad was adamant that one civilian had been killed - although he said he could not be sure who fired the fatal bullet.